Cellulosic product and process of producing same



Patented Dec. 3, 1940 PATENT. OFFICE A CELLULOSIC PRODUCT AND PROCESS OF 1 PRODUCING SAME Heinrich Lohmann, Baden, Germany, asslgnor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing.

8 Claims.

The present invention relates to yarns, ribbons, tapes,'tllms, sheeting, caps, bands, lacquers, coating compositions, draperies, fabrics, upholstery, and like articles and materials containing, or consisting of organic esters of cellulose. Particularly, the present invention relates to a process of preserving the strength of such materials against deterioration upon exposure to the deleterious action of solar light.

10 More particularly, the invention relates to pigmented materials containing, or consisting of organic esters of cellulose and exhibiting a retention of strength upon exposure to solar light. For convenience, the invention will be discussed 1 hereinafter in terms of cellulose acetate.

One object of the present invention is to prevent, at least to a major extent, the loss in strength normally incurred by cellulose acetate materials upon exposure to solar light.

Another object of the present invention is to diminish the normal tendency of cellulose acetate materials tofade upon prolonged exposure to solar light.

A particular object of the present invention is to decrease the normal tendency of dyed cellulose acetate articles to fade in color upon prolonged exposure to solar light.

A more particular object of the present invention is to increase the resistance of suitings,

outer wearing apparel, upholstery, draperies, fabrics, ribbons, films, sheeting, caps, bands, lacquers and the like containing or consisting of pigmented cellulose acetate materials to the deleterious action of solar light.

In accordance with the present invention, the above objectives, as well as other objects hereinafter becoming apparent, are accomplished by incorporation of a manganous compound in the cellulose acetate materials.

In the preferred embodiment of the invention, an amount of a manganous compound sufficient to impart the desired resistance to the deleterious action of solar light, but insufiicient to interfere with the desired color or transparency of the finished article is incorporated into a titanium dioxide pigmented cellulose acetate material. That is to say, depending upon the character- 50 istics desired in the particular article being made, about 0.05% to 10% of the manganous compound by weight on the basis of the cellulosic structure is incorporated. The manganous compound is preferably a manganous salt that is at least somewhat soluble in the solvents used Application June 25, 1938, Serial In France June 28, 1937 in cellulose acetate spinning solutions, for instance ethyl alcohol and/or acetone.

The following examples are given as illustrative of the invention, and are not intended to be limitative.

Example I To a solution of 25 kilograms of cellulose acetate and '15 kilograms of acetone containing 500 to 750 grams of titanium dioxide is added a di- 10 lute aqueous solution containing 125 grams of manganous lactate. After thorough agitation to secure the requisite homogeneity, this solution is converted into yarn by a. standard dry spinning process. 1

After 150 hours exposure to sunlight under a 3 millimeter pane of ordinary glass, the pigmented cellulose acetate yarn thus obtained and containing about 0.5% manganous lactate exhibits a loss in strength of only about 5%. In 20 contrast, a normal, unmodified, pigmented, cellulose acetate yarn shows a loss of 50% in strength for the same length of exposure to light under the same conditions.

Example II 25 After a standard securing and desizing operation, a taffeta composed of undelustered .cellulose acetate yarn is dipped into a 5% solution of manganous nitrate. Upon whizzing and dry- 30 ing, the fabric is found to be impregnated with about 1% of manganous nitrate, and upon exposure to sunlight, it exhibits much less deterioration than an untreated cellulose acetate fabric.

The cellulose acetate yarns or fabrics prepared in the above examples may be submitted to the action of soap baths normally employed for removing size or other dressing from cellulose acetate materials without substantially decreasing the improved resistance to light deterioration. Moreover, the so treated cellulose acetate materials not only exhibit less tendency to fade upon exposure to light, but also a dyeing of such yarn and fabric exhibits an appreciable increase in fastness to light.

The manganous compound should be at least somewhat soluble in organic solvents such as acetone and/or ethyl alcohol. Among a host of manganous salts that are suitable may be mentioned manganous acetate, manganous resinate, manganous propionate, manganous citrate, manganous tartrate, manganous succinate, manganous lactate, manganous chloride, manganous thiocyanate, etc. To the extent that compatithe case of outer wearing apparel such as mens suits, womens dresses, draperies, paint, lacquers, or similar applications wherein exposure to solar light is continued. and prolonged and/or wherein a slight coloration is permissible, a quantity approaching the upper limit of about 10% of the manganous salt may be incorporated. In certain cases, if desired, in order to prevent any substantial development of objectionable color a small amount of a suitable reducing agent may be incorporated with the manganous compound.

Obviously, the manganous salt may be incorporated in the cellulose acetate materials in various ways.. If desired, for example, the manganous compound may be intimately and uniformiy distributed in the delustering pigment, such as titanium dioxide, before the same is added to the solution from which the article is made, or the manganous salt may be applied in the form of a yarn dressing composition at any suitable stage in the manufacture of the yarn, or the manganous salt may be applied by impregnation from a bath during a fulling or other finishing operation. It is distinctly preferable that the manganous salt be incorporated in the spinning solution, since this mode of procedure insures retention of manganous comound in the final cellulosic product, even after various finishing operations.

While distinctly valuable for increasing the light resistance of undelustered cellulose acetate material, the greatest value of the invention resides in its application to pigmented cellulose acetate material. Particularly is this true of cellulose acetate materials pigmented by incorporation of titanium dioxide. However, the invention comprehends usage also in cellulose acetate materials delustered with other pigments. As typical of such other pigments may be mentioned barium sulfate, calcium sulfate, calcium titanate; zirconium oxide, zinc stearate, and organic pigments such as diacetyl benzidine, dibenzoyl benzidine, and diacetyl toluidine.

The cellulose acetate article modified with the manganous salt may have present a plasticizer or various other modifiers. For instance, the cellulose acetate material may have also present amine polymer modifiers of the general nature described in the copending application of W. W. Heckert Serial No. 143,829, filed May-20, 1937, said modifiers rendering the cellulose acetate receptive to various dyes.

The process of the invention yields cellulose acetate products possessing superior resistance to light deterioration. This superior resistance to light deterioration is particularly positively shown in the retention of strength, resistance to fading, and resistance to fading of dyed or pigmented cellulose articles containing the manganous salt. Obviously, such characteristic improves the serviceablity and widens the appeal of articles made from cellulose acetate. Thus,

outer wear such as mens suits and women's dresses may be made from cellulose acetate continuousor staple fiber yarns, alone or mixed with wool, cotton, silk, or regenerated cellulose, with increased assurance that the customer will be satisfied with the permanency of the strength and the fastness of the dyeing. The same is true also of bathing suits, for which cellulose acetate is otherwise admirably adapted. Broadly, of course, the invention is of benefit wherever an article consisting of or containing cellulose acetate is exposed for long periods to solar light. Among the many such useful applications may be mentioned draperies, awnings, washable window shades lacquered with cellulose acetate, caps,

lose, propyl cellulose, benzyl cellulose, and mixed.

organic ester-ether derivatives of cellulose.

The invention may also be applied to regenerated cellulose yarn, staple fibers, tire cord or like materials whether produced by the viscose or cuprammonium process with beneficial results.

Parts, percentages and proportions stated throughout the specifications are intended to be parts, percentage and proportions by weight unless otherwise specified.

Any departure from the above description which conforms to the principle of the invention is intended to be included within the scope of the claims.

I claim:

1. A pigmented cellulose acetate containing manganous lactate in an amount approximating 0.5% to 10% by weight of the cellulose acetate, and possessing improved resistance to the destructive influence of solar light.

2. Cellulose acetate pigmented with a delustering titanium compound and containing manganous lactate in an amount approximating 0.5% to 10% by weight of the cellulose acetate, and possessing improved resistance to the destructive influence of solar light.

3. Pigmented cellulose acetate yarn containing manganous lactate in an amount approximating 0.5% to 10% by weight of the cellulose acetate .yarn, and possessing improved resistance to the destructive influence of solar light.

4. Cellulose acetate yarn pigmented with a delustering titanium compound and containing manganous lactate in an amount approximating 0.5% to 10% by weight of the cellulose acetate yarn, and possessing improved resistance to the destructive influence of solar light.

5. A process for preserving the strength and color against exposure to light of delustered yarn containing cellulose acetate which comprises incorporating into the spinning solution of cellulose acetate and organic solvent from which said delustered yarn is spun, a delustering material and manganous lactate in an amount approximating 0.5% to 10% by weight of the cellulose acetate in said spinning solution.

6. A process for preserving the strength and color against exposure to light of delustered yarn containing cellulose acetate which comprises incorporating into he spinning solution of cellulose acetate and organic solvent from which said compound and manganous lactate in an amount approximating 0.5% to 10% by weight of the cellulose acetate in said spinning solution.

7. A process for preserving the strength and:

color against exposure to light of yarn containing cellulose acetate which comprises incorporating into the spinning solution of cellulose acetate and organic solvent from which said yarn is spun, manganous lactate in an amount approximating 0.5% to 10% by weight of the cellulose acetate in said spinning solution.

8. A. ce'l1u1osic structure selected from the group consisting of esters of cellulose with organic fatty acids, ethers of cellulose, mixed esterethers of cellulose with organic acids, and regenerated cellulose containing manganous lactate in an amount approximating 0.5% to 10% by ,weight of the cellulosic structure, and possessing improved resistance to the destructive influence of solar light. 

